I held artwork surveys for bumble bees at each and every of one’s 7 internet sites in the same about three census periods even as we counted flowery financing diversity (dos8 May to help you eight Summer, 22-31 Summer, 22-30 July). For every single of your about three bumble bee surveys, we decided to go to per site three times, shortly after during each one of three time periods (0800-1100, 1100-1300, 1300-1700 period). All testing was carried out towards the sunny weeks that have heat between 19 and you can thirty two°C.
We caught and you may marked for every bumble bee having a tiny mark off colored correction liquid on the thorax to quit relying someone more than once while in the a sampling period within a website. We recorded bumble-bee species, status, in addition to plant varieties on which the bumble-bee try discovered foraging and you will create the latest bee. We spent 31 min each head to during the one or two internet sites having an area of ?dos,000 m 2 , 45 min in the two 10,000-meters dos internet, 90 min within two 29,000-m 2 internet sites, and you may 120 minute from the one or two 70,000-meters 2 websites. I checked out to own a sampling date prejudice using rarefaction (get a hold of Analytical Studies)parisons off variety away from bees caught each hour to help you money beliefs otherwise environment types eliminated prospective testing date biases.
I known bumble bees on the planet having fun with Mitchell (1962) as a primary power; getting definitions regarding regional varieties, we utilized Medler and you will Carney (1963). Hendrix from the School out-of Iowa. The fresh new plant types were later on classified because the indigenous otherwise delivered so you’re able to get to know perhaps the bumble bees, which are indigenous, shown preferences to possess indigenous blooming species.
Statistical Analyses.
We used the log2 Shannon-Wiener index to calculate bumble bee species diversity using cumulative abundances across all censuses. We also used cumulative abundances of ramets of plant species visited by bumble bees to obtain seasonal totals of available floral resources for each site. Plants included on the list were those from which we captured bumble bees in this and related studies (C. Gienapp, unpublished data). Only rarely did a plant species appear in more than one census, and therefore it is unlikely that the same ramets were counted twice in seasonal abundance measures. We examined plant diversity using the Simpson index rather than the Shannon-Wiener index because the former is less sensitive to rare plant species. These rare species are unlikely to have a strong effect on bumble bee diversity and abundance.
We known potential predictors off bumble bee diversity and you may variety for each hours having fun with original easy regression analyses contrasting them resistant to the payment and you can LRI of each and every private and you can combined land variable ( Dining table 2) from the one another five hundred- and you can 700-yards radii and you may webpages variables (abundance, range, and occurrence out-of bumble bee-went to flowering ramets). Landscaping predictors showing relevance, which picked for further analyses was in fact LRI of your surroundings at five-hundred and you will 700 yards (that have and you can with no website) and percentage of joint grasslands regarding landscape ( Dining table dos). We made a decision to explore LRI viewpoints having and you can without any web site provided to examine the newest relative efforts of flowery types of this new landscape and you will webpages alone to help you range and you can wealth including the result of the landscaping and web site joint. Tall web site predictors have been Simpson variety, abundance, and density off flowering ramets of plant types decided to go to from the bumble bees.
Discount specimens from bumble bees are located in the fresh new distinct Stephen D
I made use of Pearson product-minute correlation analyses to examine having collinearity between potential predictors out of bumble-bee assortment and abundance per hour prior to multiple regression research. Diversity, variety, and occurrence out-of blooming ramets at the site weren’t coordinated to the LRI of your land (with and with no webpages provided) at five-hundred- or 700-meters radii (all r 0.16). But not, discover weakened collinearity amongst the website characteristics off thickness and you will abundance off blooming ramets regarding types employed by bumble bees (r = 0.668, P = 0.07), and only one of them a napsauta linkki heti couple regional procedures from info is used in a regression model. In most designs, i only use predicators exhibiting no collinearity (P > 0.10).